The use of information carrier plates (also referred to as phosphor plates or phosphor storage plates) for obtaining visually perceptible contrast upon exposure to X-rays is known in the art as computed radiography (CR) and is described for example in U.S. Pat. No. 7,211,785 (Berger), incorporated herein by reference.
The imaging cycle employing such plates comprises juxtaposing the plate nearby a specific part of the body (e.g., leg, arm, tooth, and the like) and then exposing the plate to X-rays in order to obtain an image from stored radiation energy. Following exposure, the plate is then removed from the patient and the latent image that is stored thereon is scanned by a laser beam or other energy source to stimulate emission of the stored energy and to form corresponding image data from the emitted energy. After the plate has been scanned, the obtained image data can be displayed and stored for further examination. The exposed and scanned plate is then erased and can be reused in a subsequent imaging cycle.
It can be appreciated that each plate is preferable to properly tracked throughout the imaging cycle as the plate circulates from X-ray exposure, to scanning, to erasure, and to re-use. That is, at each stage in this process, to know specific plate identification information as well as patient identification information and identification information concerning specific treatment with which a plate is associated.
This is preferred for general medical computed radiography (CR) and becomes especially complex for intra-oral dental computed radiography applications. In dental clinics, large numbers of patients undergo X-ray examination, and therefore a large number of information carrier plates can be in circulation at any one time, thus increasing the probability for mismatch between a particular plate and the patient and treatment data associated with the plate, as well as with the obtained image on the plate. The probability for mismatch is high in a working environment where several treatment rooms, each equipped with an X-ray generator, share the same scanning device. A mismatch can result in confusion, delay, waste, incorrect diagnosis, and the need to repeat an exposure in some cases. Other possible errors that can occur due to mismatch include inadvertent re-exposure of a plate that has not yet been erased.
The likelihood for error and the impact of an error can be further compounded when a full mouth scan is executed. This dramatically increases the number of plates used for a particular patient and requires careful tracking to avoid mistakes.
With intra-oral dental computed radiography, the mismatch between CR plates is not easily detectable by the technician, since different teeth can have a relatively similar appearance. The likelihood of confusion is high when compared with other medical radiography applications that image larger or more distinctive parts of the body about which there can be much less confusion.
Thus, positive and unequivocal identification, as well as monitoring and tracking of information carrier plates, is desired in computed radiography in general, and in intra-oral dental computed radiography in particular, since it helps to prevent patient mismatch and other errors.
There have been a number of attempts to address this issue. One example can be found in U.S. Pat. No. 5,428,659 (Renner) describing digital memory configured as a PCB (printed circuit board).
In intra-oral dental computed radiography, the exposed information carrier plates are usually placed on a flat holder that is divided into cells referring to different teeth. A technician puts the CR carrier plates on the holder such that a certain plate occupies a certain cell. The pattern of the cells corresponds to the pattern of a template that is filled in by the dental practitioner before submitting the plates to X-ray exposure. The plates are moved from the treatment station to an X-ray station and then to a scanning station, lying on the holder in the order corresponding to the template pattern. In particular situations, this arrangement can be unreliable, for example, the plates can fall from the holder during handling. Their correct re-attribution to the corresponding cell can be complicated if the plates are not provided with some type of identification means.
Radio Frequency Identification Devices (RFID devices) are known for identification, tracking, and monitoring of various items. RFID tracking is used for identifying various items, like consumer goods, reusable and disposable items, people, animals, and the like. This identification technology has been implemented in various technical and non-technical fields, including medicine.
An RFID system comprises two main components: (i) a transponder associated with an item to be identified, and (ii) an interrogator, separated from the transponder by a short distance. The RFID interrogator comprises an antenna, a transceiver and a processing device. The interrogator component sends RF energy and an interrogating signal (if necessary) to the transponder and then receives an RF response signal from the transponder. The received signal is transferred to the processing device and is read.
The RFID transponder, or so-called RFID tag, is affixed by a suitable method to the item to be identified and comprises an integrated circuit containing RF circuitry. This circuitry serves as memory for storing information to be transmitted as a signal to the processing device in the interrogator. The RFID tag also comprises an antenna for transmitting this signal. Reading the signal that has been sent by the transponder allows the item bearing the tag to be identified and monitored.
There have been attempts to implement this technology in computed radiography. Some examples are noted below.
U.S. Pat. No. 7,319,396 and U.S. Pat. No. 7,518,518, both to Homanfar, et al., describe using an RFID tag.
U.S. Pat. No. 7,095,034 (Haug) describes image carriers enclosed in cassettes, with an RFID tag affixed to the edge region of the cassette.
U.S. Pat. No. 5,418,355 (Weil) describes storage media enclosed in a cassette wherein the media is provided with an identification bar code.
U.S. Pat. No. 4,739,480 (Oono) describes a label adhered to the image storage panel, with the panel stored in a cassette. The information carried by the label represents an identification code assigned to the panel. U.S. Pat. No. 6,359,628, U.S. Pat. No. 5,757,021 (Dewaele) and EP Patent No. 0727696 (Dewaele) describe media contained in a rigid cassette with an RFID tag attached to a specific location on the cassette.
U.S. Pat. No. 4,960,994 (Muller) describes media that is used in association with a cassette and with a memory affixed to the cassette in a predetermined location. U.S. Pat. No. 6,381,416 (Manico) describes use of an RFID tag in association with photographic film used in consumer photography, for example, for establishing conditions to be selected for processing of the film.
While such arrangements may employ RFID devices to help support the use of X-ray cassettes, however, there can be little or no improvement to the workflow process for dental imaging. Persistent problems such as inconsistent labeling of plates, poor tracking of plate usage, and potential mismatch of images to patients continue to impede workflow efficiency in large dental practices.
In U.S. Ser. No. 12/976,011, entitled METHOD AND SYSTEM FOR COMPUTED RADIOGRAPHY (Amir) which published as US Publication No. 2012/0001737, there is described a method and a system with workflow process which can be employed for dental imaging. The system employs an RFID interrogator, also referred to as a tagging device. The system employs imaging plates provided with RFID transponder and a scanner provided with RFID interrogator. By means of the tagging device, the required temporary information, e.g. patient identification information, is written in the transceiver component affixed to imaging plates.
Depending on the implementation, aspects associated with marketing of such a system could arise, for example, if the system comprises more than one tagging devices intended for use in a clinic provided with a single scanner or with several scanners.
For example, a dealer can purchase four tagging devices by a discounted price of three and then to sell them to four clinics while always charging full price for each tagging device. Similar situation can arise when spare parts are sold by the manufacturer at a discounted price to the dealer.
This situation could be prevented for example by providing the system components with an identification means bearing identification information and selling the system and/or its components with a license media bearing this tag. The identification information would refer inter alia to the amount of licenses available for those components which are permitted for use.
By virtue of this provision it would be possible to link the identification information with certain tagging device and/or with certain spare part and/or with certain scanner. When this link is established the use only of those components of the system or its software would be permitted which are covered by a purchased license.
Furthermore, during the use of such a system a situation can arise, when the entire scanner or its controller board should be replaced due to malfunction. In this situation when the replace scanner is installed the calibration parameters and/or other set up parameters associated with the malfunctioning scanner would be lost and their resetting would be required for the replacing scanner. Here again it would be desirable to provide the scanner with an identification tag storing the unique setting parameters and which could be easily transferable to the replacing scanner.
There have been attempts to deal with similar issues in various technological fields. Some examples are noted below.
WO 2007118591 describes an accessory kit for use with a software based medical resource to perform a particular medical procedure. This kit includes a package, a license media with license key information and an item for performing the medical procedure. One type of license media used is an RFID tag.
US 2006/133609 describes an authentification apparatus equipped with authentification tag and a reading and recording drive that includes a transmitter and a coupler chip. The authentification tag and the transmitter are capable of communicating when the reading medium or the recording medium is coupled to the reading or recording drive.
US 2007/001852 describe wireless rights management, e.g. programs by using an RFID tag with authorization information.
GB 2456452 describes software copyright protection and licensing system using RFID. A RFID tag is supplied with a software package. During installation of the software package in a computer, a RFID reader interrogates the RFID tag for a product installation and licensing key. During installation of the software, an installation signature is generated and stored in the RFID tag and computer.
While there have been attempts to employ RFID technology for securing access to a system, there is room for improvement in providing an RFID solution for a license media tailored for specific workflow requirements of computed radiography in general and dental computed radiography in particular.